#include<stdio.h>
int n;
int fbi(int i)
{
	if(i == 1)
		return 1;
	else if(i == 2)
		return 1;
	else return fbi(i-1) + fbi(i-2);
}
int main()
{
	while(scanf("%d", &n) != EOF)
	{
		printf("%d\n", fbi(n));		
	}
}
